Field of the Invention
The invention relates to a device for culturing cells in a bioreactor, the waste-air line of which leading out of the reactor interior comprises a waste-air filter having a sterile-filtration microfilter membrane.
Description of the Related Art
In order to culture cells in a bioreactor, a relatively large air flow must be reliably supplied to and discharged from the reactor interior forming a closed culture chamber. While this is done, cells (e.g. microorganisms) must be held back both from the outside to the inside and from the inside to the outside. The reactor interior or the culture chamber is generally operated under elevated temperature with an aerated aqueous solution containing nutrients and cells (e.g. microorganisms) to be propagated.
According to the prior art, hydrophobic sterile-filtration microfilter membranes which are, for example, qualified in accordance with ASTM 838-05 are used. Preferably, said membranes are hydrophobic to the extent that, firstly, no water penetrates into the filter membrane structure and, secondly, no closed water film can form on the filter membrane surface and thereby restrict or stop the air flow through the filter membrane. If water vapor is carried out of the solution with the air flow, it condenses at least in part on the filter membrane and all housing and pipeline parts and must be discharged. At high air flows in particular, cells, cell debris or particulate substances, for example nutrients or residues thereof, are carried along onto the filter membrane surface and block the pore structure of the filter membrane.
DE 10 2008 025 968 A1 discloses a device for culturing cells in a bioreactor, the waste-air line of which leading out of the reactor interior comprises a hydrophobic sterile filter or waste-air filter having a microfilter membrane. In order to avoid the condensation of water vapor on the filter membrane, a condenser is placed upstream of the waste-air filter in the case of the known bioreactor, which condenser cools down warm moist waste air and recycles dripping water into the reactor interior. Although this was fundamentally proven to be effective, it is relatively cost-intensive and cannot prevent cells, cell debris or particulate substances from being carried onto the filter membrane surface and blocking said surface.
It is an object of the present invention to improve the known device for culturing cells to the extent that it, firstly, can be produced cost-effectively and that it, secondly, in addition to avoiding a blockage by water vapor, also prevents a blockage of the microfilter membrane by cells or particulate substances.